The present invention relates to a liquid-crystal display device and, more particularly, to an active matrix array substrate having thereon a plurality of switching elements arranged in a matrix and a plurality of wirings connecting the elements.
An active matrix liquid-crystal panel having a switching element array formed on a large-size substrate made of a glass is put into practical use, and thus as a thin, light-weight display device, may replace conventional CRTs. The active matrix-array plate having thereon a plurality of active switching elements arranged as a matrix and a plurality of wiring connecting them to one another is fabricated by repeating the depositing and patterning of a semiconductor layer, an insulating film and a conductive film on the substrate.
Thin-film transistors (TFTs) are used as active switching elements and arranged in a matrix consisting of rows and columns. The TFTs arranged in the same row have respective gates connected in common to a gate wiring which is in turn connected to gate terminal receiving a gate drive signal. On the other hand, the drains of the TFTs arranged in the same column are connected in common to a drain wiring which is in turn connected to a drain terminal receiving drain drive signals. The source of each of the TFTs is connected to a transparent electrode constituting a pixel.
The gate wirings are arranged in rows with a predetermined pitch according to the size of each pixel, and the drain wirings are arranged in columns similarly. On the other hand, in view of the connection to a driving IC for applying the respective drive signals to the gate and drain terminals, the gate and drain terminals are arranged with a pitch that is considerably smaller than the pitch of the gate or drain wirings.
The gate and drain wirings and the gate and drain terminals are formed by forming a conductive film on a glass plate and then selective removing the conductive film by means of the so-called photoresist process. In the photoresist process, however, if dust contamination occurs, a portion or portions of the conductive film would undesirably remain, although such portions should have been removed. The portions of the conductive film thus left are so small that no substantial short-circuit occurs between the gate wirings or the drain wiring in the matrix array. As described above, however, the pitches between gate terminals and between drain terminals are so small as to allow such portions of the conductive film to produce short-circuits between these terminals. There is further a tendency to produce short-circuits between adjacent ones of partial wirings for connecting the respective terminals to the gate and drain wirings.